The author is Professor Emeritus of Dairy Nutrition at Cornell University.
Red clover is a forage legume that may be suitable in certain situations as a replacement for alfalfa. This forage can grow on soils unsuitable for alfalfa. These include poorly drained soils and a wide pH range (5.8 to 7). In this situation, the yields of red clover may have higher yields than those of alfalfa.
There are differences in nutritional composition between alfalfa and red clover. The crude protein content can be similar, but red clover contains less soluble protein and more undegradable protein in the rumen. This is due to the polyphenol oxidase enzymes of red clover. Fiber levels can also be similar to alfalfa, but red clover has lower lignin and higher digestibility of neutral detergent fiber (NDF). However, the rate of decline in fiber digestibility with advancing maturity is slower for red clover. Data from trials in New York City revealed that red clover was higher in sugars and lower in starch than alfalfa.
Several studies have been conducted at the University of Wisconsin and the USDA Dairy Forage Research Center to compare alfalfa and red clover silages in dairy cattle feed. The diets used were 50-70% forage in the dry matter of the total ration. The forage portion of the rations consisted of 100% alfalfa or red clover silage. Dry matter intake tended to be lower with red clover silage diets, but this was statistically different in only three of the seven reported trials. Milk production was higher with the red clover diets in one trial and lower in two other trials. Nitrogen use efficiency and energy digestibility tended to be higher when red clover silage was used.
In one trial, the diet of cows on the red clover diet contained less high moisture corn on the cob and more soybean meal than the grain mixture fed with alfalfa silage. Dry matter intake was depressed with the red clover diet. Milk production, milk fat, milk protein, and 3.5% corrected milk were not different between the alfalfa and red clover diets. Feed efficiency (pounds of milk per pound of dry matter ingested) was higher with the red clover diet. Dry matter, NDF, and nitrogen digestibility were higher in cows fed the red clover diet.
A later article by Wisconsin researchers used diets containing 65% forage. The alfalfa silage diet consisted of 5% corn silage, 47% alfalfa silage and 13% grass silage as a percentage of the dry matter of the total ration. The treatment regimen consisted of 5% corn silage and 60% red clover silage. Dry matter consumption was approximately 2.5 pounds lower with the red clover silage diet. Milk production was not statistically different. Energy-corrected milk was lower in the red clover diet due to the lower fat and protein content of milk. Feed efficiency was higher with the red clover diet. Milk urea nitrogen was lower for cows fed the red clover diet, while the efficiency of using dry matter, NDF and nitrogen was higher.
A suitable alternative
Tom Kilcer of Advanced Ag Systems in New York replicated plot trials comparing alfalfa and red clover forages. There were three locations in New York City with different growing degree days. We used the Cornell Net Carbohydrate and Protein System model to predict metabolizable energy (ME) and metabolizable protein (MP) milk production. The diet used consisted of 65% forage, 60% of the forage being in the form of corn silage and 40% in the form of alfalfa or red clover.
The alfalfa and red clover forages used were 40% NDF. The grain mix and dry matter consumption were the same for both forages. The alfalfa silage used was 20% crude protein. The three red clover forages contained 16.6%, 17.8% and 16.9% crude protein. The crude protein in alfalfa was 20%, 19.3% and 17.8%.
The table contains the results of these diet simulations. PM milk was lower at Site 1 because red clover was less rich in crude protein than alfalfa. ME and MP milks were higher at site 2, mainly due to the higher digestibility of NDF in red clover. ME and MP milks were similar at site 3.
The results of these studies indicate that red clover may be an alternative to alfalfa. A key factor in this decision will be the soil type, drainage and soil pH. Red clover has higher fiber digestibility than alfalfa and less soluble and degradable protein in the rumen. This provides more non-degradable protein in the rumen and more microbial protein. The amount of a bypass protein source in the dairy diet may be less when using red clover diets, which can reduce the cost of food purchased.
A lower cost protein source can be used as a substitute to provide additional protein when red clover is fed. There appears to be less concern about the decrease in dry matter consumption when red clover is mixed with other forages. Forage analysis should include NDF digestibility to take advantage of red clover in dairy cattle diets.
This article appeared in the January 2022 issue of Hay and fodder producer on page 15.
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